Prelminary

MB91401

2004.11.12

HANDLING DEVICES

Preventing Latch-up

When a voltage that is higher than VDDE and a voltage that is lower than VSS are impressed to the input terminal and the output terminal in CMOS IC or the voltage that exceeds ratings between VDDE to VSS is impressed, the latch-up phenomenon might be caused. If latch-up occurs, the supply current increases rapidly, sometimes resulting in thermal breakdown of the device. Use meticulous care not to let any voltage exceed the maximum rating during device operation.

Separation of power supply pattern

Analog PLL (APLL at the following) is installed in this LSI. The power supply for VCO and for digital is separated in LSI so that the oscillation characteristic of APLL may receive the influence of power supply variation.

Therefore, the power supply is recommended to be separated also on the mounting base.

Separation of power supply pattern (recommended)

Take measures to reduce impedance, for example, by using as wide a power pattern as possible. The recommendation example is shown as follows.

For two power supplies (for digital and for VCO)

It is advisable to provide a digital power-supply (a) and VCO power-supply (b) and connect them to the LSI’s equivalents, respectively.

Figure For 2-power supply (for digital and for VCO)

Power supply

(a)

VDD (for digital)

PLLVDD (for VCO)

Power

 

supply

PLLVSS

(b)

 

APLL

LSI

Logic part

VSS

• For the common power supply

To share a single power-supply for digital and VCO uses, it is advisable to separate the output into the digital and VCO wiring patternsand connect them to the LSI.

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Fujitsu MB91401 manual Handling Devices, Preventing Latch-up, Separation of power supply pattern

MB91401 specifications

The Fujitsu MB91401 microcontroller is a versatile device designed for automotive applications, embedded systems, and industrial control. It belongs to the MB91400 series, known for its robustness and efficiency. This series integrates advanced features and technologies that cater to a wide variety of real-time applications.

One of the standout features of the MB91401 is its 32-bit RISC architecture, which operates at clock speeds up to 40 MHz. This high-performance core enables rapid processing and data handling, making it suitable for demanding applications. The microcontroller is equipped with a generous amount of Flash memory, allowing developers to store essential firmware and applications directly on the chip, enhancing reliability and reducing design complexity.

Another key characteristic is its extensive memory configuration, which includes SRAM for data storage and EEPROM for non-volatile data retention. This combination provides flexibility for developers, enabling them to tailor the memory allocation based on specific application requirements.

The MB91401 is designed with a focus on peripheral integration. It features multiple I/O ports, timer units, and A/D converters, making it an ideal choice for applications that require precise timing and analog signal processing. The analog-to-digital converters offer high resolution and fast conversion speeds, which are critical in automotive and industrial control systems where accuracy is paramount.

Safety is a critical consideration in automotive applications, and the MB91401 addresses this with built-in diagnostic features and error detection capabilities. These features help ensure that the application remains functional and safe under various operating conditions.

In terms of connectivity, the microcontroller supports various communication protocols, including CAN, UART, and SPI, facilitating seamless integration with other systems and devices. This is particularly important in automotive applications where communication between different electronic control units (ECUs) is essential for overall system functionality.

The Fujitsu MB91401 is also designed for low power consumption, making it suitable for battery-operated devices and energy-sensitive applications. Its various power-saving modes allow developers to optimize the system's performance while extending operational life.

In summary, the Fujitsu MB91401 is a powerful and flexible microcontroller that combines high-performance processing with extensive peripheral support and safety features. Its robust architecture and energy-efficient design make it an excellent choice for a wide range of automotive and industrial applications, promoting both reliability and innovation in embedded system development.